Mini Splits Suck

A Letter From Your HVAC Technician

Dear Homeowner,

You know how sometimes you’ll meet a pool guy who spends every day cleaning, repairing and maintaining swimming pools…

…and then tells you he’d never own a pool?

Welcome to mini splits.

Ask a homeowner about their mini split and you’ll hear:

“I love this thing.”

Ask the HVAC technician who has to diagnose it when it stops working and you may get a slightly different response.

Don’t misunderstand us.

Mini splits are incredibly efficient. They’re quiet. They don’t require traditional ductwork. They provide excellent individual temperature control. And there are applications where they’re one of the best HVAC solutions available.

We install them.

We service them.

We recommend them.

We just don’t necessarily want one in our own house.

Allow us to explain.

Love,

Your HVAC Technician

First: Mini Splits Don’t Actually Suck

Despite the title, mini splits are pretty incredible machines.

Have a converted garage?

Perfect.

An addition without existing ductwork?

Great application.

Detached workshop?

Absolutely.

An older home where installing ductwork would require dismantling half the house?

Now we’re talking.

Mini splits solve problems that conventional central HVAC systems sometimes can’t solve economically or practically.

They can also achieve extremely high efficiency because inverter-driven compressors can adjust their capacity to match the needs of the space instead of simply operating at 100% and shutting off.

That’s the good stuff.

And if that’s all we ever saw?

We’d probably love them too.

Unfortunately…

We also have to fix them.

You Bought an Air Conditioner. We Inherited a Computer Network.

This is where the relationship starts getting complicated.

Traditional HVAC equipment has become considerably more sophisticated too, especially modern inverter systems.

But mini splits can take manufacturer-specific electronics to another level.

You press the remote.

Nothing happens.

Wonderful.

Is it the indoor board?

Outdoor board?

Communication wiring?

Temperature sensor?

Coil sensor?

Fan motor?

Electronic expansion valve?

Power supply?

Inverter?

Or has the machine simply decided that today isn’t a good day?

Many ductless systems rely heavily on electronics, sensors and communication between the indoor and outdoor equipment.

When everything works?

Beautiful.

When it doesn’t?

Your technician may be standing in your driveway reading a 96-page service manual on his phone.

This is why the pool guy doesn’t own a pool.

“But It Has an Error Code!”

It sure does.

That’s actually helpful.

Sometimes.

Your mini split starts flashing:

Great.

We pull up the service manual.

“Communication or system abnormality.”

Thank you.

We’ve successfully narrowed the problem down to:

The air conditioner.

Now comes the actual troubleshooting.

Error codes can point a technician in the right direction, but they don’t necessarily tell us which component has failed.

A communication error might involve wiring.

Or a board.

Or a sensor.

Or power.

Or another component causing the communication problem.

The error code is often the beginning of the diagnosis.

Not the diagnosis.

“Why Is the Fan Still Running?”

Ah, yes.

You set the mini split to 72°F.

The room reaches 72°F.

The compressor slows down or shuts off.

And yet…

The indoor fan is still running.

So you call us.

“My mini split won’t shut off.”

Here’s the fun part:

It’s probably supposed to do that.

On many mini-split systems, the indoor fan continues operating even when the compressor isn’t actively providing full cooling.

These systems generally aren’t designed to behave exactly like the traditional central air conditioner you’re accustomed to hearing turn on, run for 15 minutes and shut completely off.

They’re designed to modulate.

So you walk underneath it.

Feel air moving.

Look at the remote.

Look back at the mini split.

Feel the air again.

“This thing is STILL running.”

Yep.

Welcome to mini splits.

The indoor fan operating doesn’t mean the compressor is running at full capacity—or necessarily running at all.

Depending on the manufacturer and operating mode, there may not even be a setting that makes it behave exactly like the conventional AC system you’re used to.

We understand why it feels broken.

It probably isn’t.

It’s just a mini split.

Every Manufacturer Has Created Its Own Little Universe

This is probably one of the biggest reasons HVAC technicians have complicated feelings about ductless equipment.

With conventional HVAC systems, a lot of diagnostic principles carry across brands.

Mini splits can be considerably more manufacturer-specific.

Different manufacturers may have their own:

Error codes
Control logic
Sensors
Circuit boards
Communication systems
Service procedures
Diagnostic tools
Replacement parts

And there are a lot of mini-split manufacturers.

Some are excellent.

They have good technical support, established distribution and replacement parts available when we need them.

And some appear to have been invented six months ago by a company whose entire technical-support department is an email address.

That’s not a huge concern while your $347 mini split is happily cooling the garage.

It becomes significantly more important when it stops.

Nobody Thinks About Parts Until They Need One

When you’re buying an air conditioner, you’re probably not wondering:

“Will someone be able to find an indoor control board for this thing seven years from now?”

We are.

Because someday you’re going to call us.

A common component fails on a conventional system?

There’s a decent chance we have it on the truck or can get it relatively quickly.

A proprietary mini-split control board fails?

Probably not.

Now we need the exact model.

We need to properly diagnose which component actually failed.

Find the part.

Verify that it’s available.

Order it.

Wait for it.

Come back.

Install it.

And make sure the board wasn’t actually the victim of another problem that caused it to fail.

This is why your technician makes that face when you tell him the brand.

You know the face.

We’re trying not to make it.

And Then There’s Cleaning Them

Oh boy.

If you’ve never seen the inside of a neglected mini-split head in Florida:

Congratulations.

The indoor unit contains an evaporator coil, blower wheel and condensate system sitting right there in your conditioned space.

Then Florida provides the ingredients:

Humidity.

Moisture.

Dust.

Time.

Eventually, the inside of that innocent-looking white box can become…

Impressive.

And properly cleaning one isn’t always:

“Spray some cleaner on the coil.”

A thorough mini-split cleaning may involve partially disassembling the indoor unit, protecting the wall and everything underneath it, installing a cleaning bib and washing the coil and blower assembly.

All while attempting not to turn your living room into a water park.

It’s delightful.

Again:

The pool guy doesn’t own a pool.

“Why Are They Still Here? I Thought These Things Were Supposed to Be Easy?”

You’ve seen the videos.

Mini split on wall.

Mini split outside.

Couple of copper lines between them.

Done.

So why have the HVAC guys been at your house for six hours?

You’re sitting there thinking:

“Why are they still here? I thought these things were supposed to be easy?”

Because installing one correctly still involves a surprising amount of work.

We have to mount the indoor unit.

Set or mount the outdoor unit.

Make the wall penetration.

Run the refrigerant piping.

Run and terminate electrical wiring.

Install the condensate drain.

Protect the lineset.

Make the refrigerant connections.

Pressure test the system.

Evacuate it.

Complete the communication wiring.

Start it.

Configure it.

Test it.

And that’s assuming your house cooperates.

Your house rarely cooperates.

Mini splits eliminate ductwork.

They don’t eliminate HVAC installation.

“$5,000?! I Can Get One on Amazon for $347.”

There it is.

We knew this was coming.

“Five grand?! I can get one on Amazon for $347!”

You absolutely can.

You can also buy a toilet at Home Depot.

The plumber still isn’t coming over to remodel your bathroom for $199.

The equipment is only one part of what you’re paying for.

A professionally installed mini split may involve refrigerant piping, electrical work, condensate drainage, mounting, wall penetrations, lineset protection, pressure testing, proper evacuation, refrigerant adjustments, startup, commissioning, labor, permitting and warranty support.

And perhaps most importantly:

Someone answering the phone when it starts flashing E7 three years from now.

You’re not buying a box.

You’re buying an installed HVAC system.

And if you genuinely want the $347 mini split from the internet?

We’re not offended.

Really.

Just understand that comparing the price of equipment sitting in a cardboard box to the price of a completed HVAC installation isn’t an apples-to-apples comparison.

One is an air conditioner.

The other is an air conditioner installed in your house.

There’s a pretty important difference.

Please Stop Putting One in Every Bedroom

This is where things get fun.

Someone discovers zoning.

Now every room needs its own head.

Master bedroom.

Guest bedroom.

Office.

Living room.

Kitchen.

Dog’s room.

Closet where you keep the Christmas decorations.

Suddenly your house has five indoor units, one outdoor multi-zone condenser and enough electronics to launch a satellite.

Yes, every room can have individual temperature control.

You’ve also multiplied the number of:

Blower motors
Control boards
Sensors
Coils
Drain pans
Drain lines
Electronic components

that may eventually need service.

Sometimes eliminating ductwork solves a legitimate problem.

But here’s something you won’t see on many mini-split advertisements:

Good ductwork is actually pretty nice.

One central air handler.

One primary filtration point.

One central condensate system.

Conditioned air distributed throughout the house.

It’s boring.

HVAC technicians occasionally develop a deep appreciation for boring.

Multi-Zone Systems Are Where the Fun Really Begins

One outdoor unit connected to several indoor heads sounds fantastic.

And in the right application, it can be.

But now multiple indoor units are connected to a single variable-capacity refrigeration system.

From a service perspective, troubleshooting can become considerably more complicated.

We’re no longer evaluating:

Indoor unit + outdoor unit.

We’re figuring out how several indoor units, electronic expansion devices, sensors, control boards and one outdoor unit are interacting with each other.

And here’s something homeowners sometimes misunderstand:

If the outdoor unit fails, all the heads connected to it can be down.

Your four-zone system gives you four independently controlled areas.

It doesn’t necessarily give you four independent air conditioners.

There’s a difference.

Cheap Mini Splits Create a Weird Repair Problem

High-quality ductless equipment from established manufacturers can absolutely be maintained and repaired for years.

But the mini-split market also contains an enormous amount of inexpensive equipment.

Eventually we encounter a strange economic question.

Do we spend hours diagnosing a proprietary electronic problem…

Find the part…

Order it…

Wait for it…

Return…

Install it…

And continue repairing an inexpensive piece of equipment?

Or does replacing the thing make more financial sense?

Sometimes a mini split isn’t technically unrepairable.

It just stops making sense to repair it.

That’s something worth thinking about before buying the cheapest unit you can find online.

So… Do Mini Splits Actually Suck?

No.

That’s the joke.

They’re actually remarkable pieces of HVAC equipment.

And sometimes they’re absolutely the right answer.

If you have a garage, addition, workshop, sunroom or another area without practical access to the central duct system?

We may recommend one.

If installing conventional ductwork would be prohibitively difficult or expensive?

Mini split.

If you want independent control of a particular space that isn’t used all the time?

There may be a very good argument for one there too.

We don’t hate mini splits.

We know mini splits.

And sometimes knowing something really, really well changes the way you feel about owning it.

Ask the pool guy about his pool.

Love, Your HVAC Technician

So if you’re considering a mini split, don’t just ask:

“How efficient is it?”

Ask:

Who manufactures it?

Who services that brand locally?

Are replacement parts readily available?

Does the manufacturer provide good technical support?

What does cleaning and maintenance involve?

What happens when a proprietary component fails?

How many indoor units do we actually need?

And most importantly:

Is a mini split really the best solution for this particular application?

Sometimes the answer is absolutely yes.

When it is, we’ll tell you.

We’ll install it correctly.

We’ll explain how it works.

We’ll show you how to use it.

And someday, when it starts flashing an error code we’ve never seen before, we’ll pull out the service manual and figure it out.

We’ll just complain about it a little.

That’s what technicians do.

And if the room reaches temperature but the fan keeps running?

Please don’t call us yet.